[SRU][J][PATCH 1/5] gve: Perform adminq allocations through a dma_pool.

[Ian Whitfield]

From: John Fraker <jfraker at google.com>

BugLink: https://bugs.launchpad.net/bugs/2109537

This allows the adminq to be smaller than a page, paving the way for
non 4k page support. This is to support platforms where PAGE_SIZE
is not 4k, such as some ARM platforms.

Signed-off-by: Jordan Kimbrough <jrkim at google.com>
Signed-off-by: John Fraker <jfraker at google.com>
Reviewed-by: Willem de Bruijn <willemb at google.com>
Link: https://lore.kernel.org/r/20231128002648.320892-2-jfraker@google.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
(cherry picked from commit 955f4d3bf0a454bc76c6393d74d844556d61b520)
Signed-off-by: Ian Whitfield <ian.whitfield at canonical.com>
---
 drivers/net/ethernet/google/gve/gve.h        |  4 +++
 drivers/net/ethernet/google/gve/gve_adminq.c | 28 +++++++++++++-------
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index 822bdaff66f6..d7de150717e4 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -8,6 +8,7 @@
 #define _GVE_H_
 
 #include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
 #include <linux/netdevice.h>
 #include <linux/pci.h>
 #include <linux/u64_stats_sync.h>
@@ -40,6 +41,8 @@
 #define NIC_TX_STATS_REPORT_NUM	0
 #define NIC_RX_STATS_REPORT_NUM	4
 
+#define GVE_ADMINQ_BUFFER_SIZE 4096
+
 #define GVE_DATA_SLOT_ADDR_PAGE_MASK (~(PAGE_SIZE - 1))
 
 /* PTYPEs are always 10 bits. */
@@ -519,6 +522,7 @@ struct gve_priv {
 	/* Admin queue - see gve_adminq.h*/
 	union gve_adminq_command *adminq;
 	dma_addr_t adminq_bus_addr;
+	struct dma_pool *adminq_pool;
 	u32 adminq_mask; /* masks prod_cnt to adminq size */
 	u32 adminq_prod_cnt; /* free-running count of AQ cmds executed */
 	u32 adminq_cmd_fail; /* free-running count of AQ cmds failed */
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
index 54d649e5ee65..50a5fa412760 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.c
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -155,12 +155,19 @@ gve_process_device_options(struct gve_priv *priv,
 
 int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
 {
-	priv->adminq = dma_alloc_coherent(dev, PAGE_SIZE,
-					  &priv->adminq_bus_addr, GFP_KERNEL);
-	if (unlikely(!priv->adminq))
+	priv->adminq_pool = dma_pool_create("adminq_pool", dev,
+					    GVE_ADMINQ_BUFFER_SIZE, 0, 0);
+	if (unlikely(!priv->adminq_pool))
 		return -ENOMEM;
+	priv->adminq = dma_pool_alloc(priv->adminq_pool, GFP_KERNEL,
+				      &priv->adminq_bus_addr);
+	if (unlikely(!priv->adminq)) {
+		dma_pool_destroy(priv->adminq_pool);
+		return -ENOMEM;
+	}
 
-	priv->adminq_mask = (PAGE_SIZE / sizeof(union gve_adminq_command)) - 1;
+	priv->adminq_mask =
+		(GVE_ADMINQ_BUFFER_SIZE / sizeof(union gve_adminq_command)) - 1;
 	priv->adminq_prod_cnt = 0;
 	priv->adminq_cmd_fail = 0;
 	priv->adminq_timeouts = 0;
@@ -212,7 +219,8 @@ void gve_adminq_free(struct device *dev, struct gve_priv *priv)
 	if (!gve_get_admin_queue_ok(priv))
 		return;
 	gve_adminq_release(priv);
-	dma_free_coherent(dev, PAGE_SIZE, priv->adminq, priv->adminq_bus_addr);
+	dma_pool_free(priv->adminq_pool, priv->adminq, priv->adminq_bus_addr);
+	dma_pool_destroy(priv->adminq_pool);
 	gve_clear_admin_queue_ok(priv);
 }
 
@@ -673,8 +681,8 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	u16 mtu;
 
 	memset(&cmd, 0, sizeof(cmd));
-	descriptor = dma_alloc_coherent(&priv->pdev->dev, PAGE_SIZE,
-					&descriptor_bus, GFP_KERNEL);
+	descriptor = dma_pool_alloc(priv->adminq_pool, GFP_KERNEL,
+				    &descriptor_bus);
 	if (!descriptor)
 		return -ENOMEM;
 	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESCRIBE_DEVICE);
@@ -682,7 +690,8 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 						cpu_to_be64(descriptor_bus);
 	cmd.describe_device.device_descriptor_version =
 			cpu_to_be32(GVE_ADMINQ_DEVICE_DESCRIPTOR_VERSION);
-	cmd.describe_device.available_length = cpu_to_be32(PAGE_SIZE);
+	cmd.describe_device.available_length =
+		cpu_to_be32(GVE_ADMINQ_BUFFER_SIZE);
 
 	err = gve_adminq_execute_cmd(priv, &cmd);
 	if (err)
@@ -747,8 +756,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	priv->default_num_queues = be16_to_cpu(descriptor->default_num_queues);
 
 free_device_descriptor:
-	dma_free_coherent(&priv->pdev->dev, PAGE_SIZE, descriptor,
-			  descriptor_bus);
+	dma_pool_free(priv->adminq_pool, descriptor, descriptor_bus);
 	return err;
 }
 
-- 
2.43.0